1,1,1,3-Tetrafluoropropene (HFO-1234ze) has a lower global warming potential (GWP) and ozone destroying potential (ODP). It is considered a potential substitute for 1,1,1,2-tetrafluoroethane (HFC-134a) and the like uses in forming agent, coolant, and aerosol propellant industries. In addition, HFO-1234ze is a good cleaning agent, for use in cleaning large-scale production equipment. HFO-1234ze is also used as a monomer for the synthesis of thermal stable, high elastic rubber materials; it is an important intermediate materials.
Currently, known methods for the preparation of HFO-1234ze include: using HFC-245fa or CFC-244fa as a starting material in a de-hydrohalogenation reaction to synthesize HFO-1234ze; using HCFC-1233zd as a starting material to first synthesize HFC-245fa and HCFC-244fa by fluorination, famed by de-hydrohalogenation to synthesize HFO-1234ze; and using HCC-240fa as a starting material to first synthesize HCFC-1233zd by fluorination, followed by further fluorination to synthesize HFO-1234ze.
U.S. Pat. No. 6,548,719, Chinese patent No. CN 1852880, PCT publication WO2008147825, etc. disclose methods using a strong alkali to dehydrofluorinate HFC-245fa in a liquid phase to produce HFO-1234ze.
Patent literatures, JP 11140002, U.S. Pat. Nos. 6,124,510, 5,986,151, CN 1852880, CN 1014666656, U.S. 2009/0118555, etc. disclose methods that uses catalysts to dehydrofluorinate HFC-245fa in the gas phase to produce HFO-1234ze.
Patent literatures, U.S. 2005/0020862, U.S. Pat. No. 4,086,407, CN 101032690A, CN 101772480A, etc. disclose methods using catalysts on carbon carrier to dehydrofluorinate HCFC-244fa to produce HFO-1234ze.
Patent literatures, CN1852880, US20050020862, U.S. Pat. No. 7592494, etc. disclose methods using HCFC-1233zd as a starting material, under the action of a catalyst, to synthesize HFC-245fa and HCFC-244fa by fluorination, and then under the action of a strong alkali, dehydrohalogenate HFC-245fa and HCFC-244fa to produce HFO-1234ze.
In the above described methods for the preparation of HFO-1234ze, HFC-245fa is expensive, HCFC-1233zd is difficult to obtain, dehydrofluorination with a strong alkali in a liquid phase will produce large volumes of liquid wastes, and the supported catalysts used in gas-phase dehydrohalogenation reaction do not have long service lives. These methods are not suitable for large scale industrial uses.
Chinese Patent publication CN101028992 discloses a method using HCC-240fa as a starting material to prepare HFO-1234ze using gas-phase catalytic fluorination. This method uses two reactors to carry out the reactions in two steps. The intermediate from the first reaction needs to be purified by distillation before use in the second reaction. The process is complicated and uses a lot of energy. It is not a reasonable use of the resource. If the two steps are carried out in a single reactor, and the reaction temperature is too high, HCC-240fa tends to polymerize and carbonize. If the reaction temperature is low, HFO-1234ze selectivity would decrease.